The present invention relates to a measurement apparatus, and in particular to an apparatus that is useful for measuring the volume of air entrained in the working fluid of a power steering pump.
Automotive power steering systems typically include a hydraulic pump and control valve connected to the discharge side of the pump, which directs pressurized hydraulic fluid at a specific flow rate to the right or left-hand portions of the power steering gear depending upon the direction that the steering wheel of the vehicle is turned by the operator. Several kinds of hydraulic pumps are used in such systems including sliding vane, slipper or gerotor types. The pumps are usually belt driven from the engine shaft and adapted to produce a volumetric flow rate that varies in proportion to the speed of the engine.
During operation of the power steering pump, air and/or other gaseous substances may become entrained in the hydraulic fluid in the form of very small bubbles. The entrained air may result in excess noise during operation of the steering pump. The noises may include whining or hissing noises. Because these noises may be similar to these caused by improper functioning components, such noise may create difficulty in evaluating whether or not the power steering components are functioning properly.
Accordingly, it would be advantageous to be able to measure the amount of air entrained in the power steering fluid when diagnosing the source of excessive power steering pump noise.
One aspect of the present invention is to provide an apparatus for measuring the amount of air entrained in the fluid of a power steering pump. The apparatus includes a fluid conduit having a connector adapted to connect to a power steering pump with the fluid conduit in fluid communication with the internal fluid cavity of the power steering pump. A pressure gauge is operatively connected to the fluid conduit for determining the pressure in the power steering pump, and a mass flow meter is operatively connected to the fluid conduit for measuring the rate at which mass is removed from the power steering pump. The apparatus further includes a vacuum pump operatively connected with the fluid conduit for drawing air out of the power steering pump.
Another aspect of the present invention is an apparatus for measuring the volume of a gaseous substance disposed within a container. The apparatus includes a vacuum pump adapted to be operatively connected with the container to generate a vacuum within the container, and a pressure gauge adapted to be operatively connected with the container to measure the pressure within the container. The apparatus further includes a device adapted to measure the change of mass within the container upon application of a vacuum to the container by the vacuum pump.
Yet another aspect of the present invention is amethod for determining the amount of a gaseous substance entrained in the liquid of a power steering pump. The method includes removing a volume of the gaseous substance from a power steering pump by applying a vacuum to the liquid disposed in the power steering pump. The mass of the gaseous substance removed from the power steering pump is determined, and the change of pressure within the power steering pump resulting from the vacuum is also determined.
These and other features, advantages, and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings.